5 feet of bell wire or some other 18-gauge wire.
A common nail
A piece of skotch tape
A 9-volt battery
A 6-volt lantern battery
10 lose staples
10 loose rubber bands
Remove about 1-inch of insulation from both ends of the wire. Wrap the wire around the nail in a single layer of tight coils in 2 or 3 layers. Use the tape to secure the wire. Attach the ends of the wire to the 9 volt battery.
What Did You See?
The 'electromagnet' was able to pick up the staples but not the rubber bands. The more loops of wire on the nail, the more staples you can pick up.
Experimenting with the Variables.
Can you pick up more or fewer staples with the 6-volt battery than with the 9-volt battery? Suppose you put two 9-volt batteries together with the 'plus' and the 'minus' terminals joined together, and then connected the wires?
How it Works:
The current flows in the wire, and each time it loops around the nail, the magnetic field produced by the nail gets a tiny bit stronger. You can measure how this strength increases with the number of windings. The strength of the field also depends on the strength of the current flowing. By taking the two 9-volt batteries and connecting them together in parallel, you have doubled the current flowing in the wire, but you still only have 9-volts of voltage.
Application to the Magnetosphere:
The electromagnet used a current of charged particles called electrons flowing through the wire to make the magnetic field. But, it is possible to get a current of charged particles flowing in space without a wire to carry them. Inside your TV picture tube, an electron 'gun' shoots a beam of electrons through space without a wire. These electrons are steared by electomagnetic forces to 'paint' a picture on the screen. In the magnetosphere, flows of charged particles create their own magnetic fields, and these magnetic fields can then interact with Earth's field and change it in complex ways.